Recently, with the advancement in radio communication technologies, an environment is being developed in which a mobile radio communication device, such as a mobile phone terminal, can simultaneously use multiple radio communication systems having different physical-layer schemes. For example, the radio communication systems include a mobile phone system, a wireless broadband system such as iBurst, and a wireless MAN system such as Wi-MAX.
To improve convenience for the radio communication device using such multiple radio communication systems, IP mobility protocols are defined, such as Mobile IPv6 (see Non-patent Document 1) and NEMO Basic Support (see Non-patent Document 2) (for instance, Non-patent Documents 1 and 2).
Non-patent Document 1: Johnson, D., Perkins, C. and Arkko, J, “Mobility Support in IPv6 RFC3775,” IETF, 2004
Non-patent Document 2: Devarapali, V, et al., “Network Mobility (NEMO) Basic Support Protocol, RFC3963,” IETF, 2005